Modified Atmosphere Packaging (MAP) for Seaweed Conservation: Impact on Physicochemical Characteristics and Microbiological Activity.

Conventional conservation techniques such as drying, salting or freezing do not allow for preserving the original characteristics of seaweeds. The present work aims to study the impact of minimal processing, in particular "Modified Atmosphere Packaging" (MAP), on the physicochemical characteristics and food safety of two seaweed species, "laver" (Porphyra umbilicalis) and "sea-lettuce" (Ulva lactuca), stored at 6 °C for 15 days. Different parameters were evaluated using analytical methods, namely the composition of headspace gases, color, texture, microorganisms, and volatile organic compounds (VOCs). The main findings of this study were that the MAP treatment was able to inhibit the respiration rate of minimally processed seaweeds, also preserving their color and texture. There was a remarkable reduction in the microbial load for P. umbilicalis treated under modified and vacuum atmospheres, and U. lactuca exhibited relatively steady values with no notable differences between the treatments and the control. Therefore, during the 15-day study period, both seaweeds met the requirements for food safety. GC-TOF-MS allowed to conclude that both MAP and vacuum treatments were more efficient in maintaining the odor characteristics of U. lactuca compared to P. umbilicalis with no significant differences throughout the storage days. Metabolic responses to diverse sources of abiotic stress seemed to account for most of the changes observed.

Proximate Composition, Physicochemical and Microbiological Characterization of Edible Seaweeds Available in the Portuguese Market.

BACKGROUND: The aim of this work was the study of the proximate composition and profile of fatty acids, minerals, and some microbiological aspects of four edible seaweed species (Chondrus crispus, Palmaria palmata, Porphyra sp., and Ulva sp.) available in the Portuguese market for food consumption, and produced in a national Integrated Multi-Trophic System (IMTA). METHODS: Moisture, ash, and total lipids were determined gravimetrically. Crude protein was analysed by Duma's combustion procedures. The total carbohydrate content was assayed by the phenol/sulphuric acid method. The assessment of the fatty acids methyl esters (FAMEs) was determined through GC-MS. Characterization of elemental analysis was performed by ICP-AES. Different standard microbiological methods were applied for microorganisms. Statistics were performed using the non-parametric Mann-Whitney U test to assess significant differences between samples. RESULTS: Lipid contents (n = 3) were very low (1.6-2.3%), particularly in Palmaria palmata, and Chondrus crispus (1.6-1.7%). The protein content (n = 4) varied from 14.4% in P. palmata to 23.7% in Porphyra sp. Carbohydrates (n = 3) were the major constituent of most seaweeds (31-34%), except in Porphyra sp., with higher content in proteins than carbohydrates. Regarding the fatty acid content (n = 4), in general, saturated fatty acids (SFAs) were the most abundant followed by polyunsaturated fatty acids (PUFAs) and monounsaturated fatty acids (MUFAs). Among macro and trace elements (n = 3), Chondrus crispus shows the highest average content in Zn (71.1 mg ⋅ kg - 1 D.W.), Palmaria palmata the highest average content in K (124.8 g ⋅ kg - 1 D.W.), Porphyra sp. the highest average content in P (2.1 g ⋅ kg - 1 D.W.), and Ulva sp. the highest average content of Ca (5.5 g ⋅ kg - 1 D.W.), Mg (55.8 g ⋅ kg - 1 D.W.), and Fe (336.3 mg ⋅ kg - 1 D.W.). In general, Na and K were the most abundant elements among analysed seaweed. Additionally, the microbiological results (n = 4) comply with the Portuguese guidelines (subgroup 2D) on the application of general principles of food hygiene in ready-to-eat foods. CONCLUSIONS: Overall, the results highlight the potential of using these seaweeds as an alternative and sustainable source of elements and bioactive compounds to produce enriched food products with a beneficial potential for human nutrition.

Dietary benzoic acid and supplemental enzymes alter fiber-fermenting taxa and metabolites in the cecum of weaned pigs.

Inclusion of enzymes and organic acids in pig diets is an important strategy supporting decreased antibiotic usage in pork production. However, limited knowledge exists about how these additives impact intestinal microbes and their metabolites. To examine the effects of benzoic acid and enzymes on gut microbiota and metabolome, 160 pigs were assigned to one of four diets 7 days after weaning: a control diet or the addition of 0.5% benzoic acid, 0.045% dietary enzymes (phytase, ß-glucanase, xylanase, and α-amylase), or both and fed ad libitum for 21 to 22 d. Individual growth performance and group diarrhea incidence data were collected throughout the experimental period. A decrease of 20% in pen-level diarrhea incidence from days 8 to 14 in pigs-fed both benzoic acid and enzymes compared to the control diet (P = 0.047). Cecal digesta samples were collected at the end of the experimental period from 40 piglets (n = 10 per group) and evaluated for differences using 16S rRNA sequencing and two-dimensional gas chromatography and time-of-flight mass spectrometry (GCxGC-TOFMS). Analysis of cecal microbiota diversity revealed that benzoic acid altered microbiota composition (Unweighted Unifrac, P = 0.047, r2 = 0.07) and decreased α-diversity (Shannon, P = 0.041; Faith's Phylogenetic Diversity, P = 0.041). Dietary enzymes increased fiber-fermenting bacterial taxa such as Prevotellaceae. Two-step feature selection identified 17 cecal metabolites that differed among diets, including increased microbial cross-feeding product 1,2-propanediol in pigs-fed benzoic acid-containing diets. In conclusion, dietary benzoic acid and enzymes affected the gut microbiota and metabolome of weaned pigs and may support the health and resolution of postweaning diarrhea.

Feeding weaned pigs diets containing benzoic acid or supplemental enzymes for 21 d after weaning changed the gut microbiota and metabolome. Benzoic acid increased feed intake, weight gain, and the presence of 1,2-propanediol in cecal digesta, which is an important microbial cross-feeding product. Dietary enzymes altered microbiota composition, increasing the presence of fiber-fermenting microbes including Prevotellaceae. Pigs fed a combination of both benzoic acid and enzymes showed improved resolution of postweaning diarrhea. These differences demonstrate the role of these feed additives in the establishment of gut microbes and metabolic pathways for the degradation of complex dietary components in the weaned pig. This study provides new information about alterations in microbial function and community composition using microbiota sequencing and metabolomic analysis.

Pleiotrophin Serum Level is Increased in Relapsing-Remitting Multiple Sclerosis and Correlates With Sex, BMI and Treatment.

BACKGROUND: Multiple Sclerosis (MS) is an immune-mediated demyelinating disease mainly affecting the Central Nervous System (CNS). 80% of MS patients present the Relapsing-Remitting form (RRMS). Pleiotrophin (PTN), a cytokine previously associated with other autoimmune and neurological diseases, could play a role in the pathophysiology of RRMS due to its neuro and immunomodulatory effect. However, PTN has never been explored in RRMS patients. AIM OF THE STUDY: To determine PTN serum levels in patients with RRMS, treated with Glatiramer acetate (GA) or Interferon-beta (IFN-ß), as well as in non-treated patients and healthy controls as a first attempt to explore PTN in RRMS. METHODS: PTN serum levels were quantified by ELISA in 57 patients and 18 controls. RESULTS: We demonstrated that PTN serum levels are significantly higher in RRMS patients. In IFN-ß treated patients alone, PTN correlated positively with time of disease evolution and time of IFN-ß use and correlated negatively with the MS severity score (MSSS). When comparing groups according to weight status, we observed that PTN is statistically increased in overweight female patients and that weight does not affect male patients. The Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve analysis was higher for males compared to females. CONCLUSION: PTN serum level is higher in RRMS patients and that is associated with sex, BMI and IFN-ß treatment. Therefore, we propose that PTN could be playing a role in MS. Further studies must be performed to identify the exact role of PTN in this pathology.

Assessing gelling properties of chia (Salvia hispanica L.) flour through rheological characterization.

BACKGROUND: Chia (Salvia hispanica L.) seeds are considered a promising ingredient for the development of functional products owing to their high nutritional value: 343 g kg-1 lipids, 251 g kg-1 protein and 226 g kg-1 fibre. Considering chia's technological capacities, mainly the ability to swell when absorbing water and gel-forming properties, its addition to a food matrix can affect texture and rheological behaviour, acting as a texturing and stabilizing agent. The aim of the present work was to assess the gelling properties of chia flour through the rheological characterization of 100, 130 and 150 g kg-1 chia flour gels. RESULTS: According to the mechanical spectra, all gels presented weak gel-like structures, as G' was always less than a decade higher than G″, but higher chia flour concentrations showed a considerable increase in viscoelastic moduli. The gels had relatively low maturation times, almost instantaneous for lower concentrations, but the cooling rate affected the dynamics of formation of the gel structure. CONCLUSION: Based on texture and rheological properties, gels with 130 g kg-1 of chia flour processed at 90 °C for 30 min showed the most suitable characteristics for use in the development of new food applications. © 2016 Society of Chemical Industry.

Optimisation of gellan gum edible coating for ready-to-eat mango (Mangifera indica L.) bars.

The optimisation of an edible coating based on low acyl (L)/high acyl (H) gellan gum for ready-to-eat mango bars was performed through a central composite rotatable design (CCRD). The independent variables were the concentration of gellan (L/H90/10) and the concentration of Ca(2+) in the coating solution, as well as the storage time after coating application. The response variables studied were the coating thickness, mango bars firmness, syneresis, and colour alterations. Gellan concentration was the independent variable that most influenced the thickness of the coating. Syneresis was quite low for the conditions tested (<1.64%). Similarly, the colour alterations were low during the entire storage time (ΔE<5). Considering the model predictions, 1.0%wt L/H90/10 with addition of 6 mM Ca(2+) could represent the optimal coating formulation for the mango bars. The release of eight volatile compounds from the uncoated and coated mango bars with the selected formulation was analysed by Headspace - Solid Phase Micro Extraction-Gas Chromatography during 9 days of refrigerated storage. This work showed that the coating can improve mango bars sensory characteristics (appearance and firmness) and stability in terms of syneresis, colour and volatiles content during storage increasing the commercial value of the final product.